NFC (Near Field Communication) is a set of short-range technologies enabling wireless communication between devices by touching them together or by bringing them into proximity. NFC operates within a radio frequency band of 13.56 MHz, and traces its roots back to the electronic tag RFID (Radio Frequency Identification).
Now, NFC finds applications in a broad spectrum of fields including payment, transmission of information about articles or goods in supermarkets or stores, travel information for tourists, traffic access control, locking systems, etc.
As the market of portable terminals such as smart phones is in explosive expansion, NFC has recently been used to impart the terminals with various functions including information exchange thereamong, payment, ticket reservation, information search, etc.
However, smart phones that have been advanced for high performance suffer from the disadvantage of heat generation from the device CPU.
To reduce heat generation in smart phones, as shown in FIG. 1, a graphite sheet 1 is attached to a battery cover 2 while being covered with a protective film 3.
Having the molecular structure depicted in FIG. 1d, the graphite sheet 1 is excellent in thermal conductivity in the horizontal direction and thus can effectively dissipate heat from a heat source. However, the graphite sheet 1 has very weak interlayer bonding strength due to its platy structure.
Accordingly, as illustrated in FIGS. 1c and 1d, the graphite sheet 1 is highly prone to peel off from the battery cover 2, thus resulting in poor product reliability.
To overcome this problem, as shown in FIGS. 2A-2C, a graphite sheet 1 is designed to be smaller in size than protective films 3 and 5 that are provided on the opposite surfaces of the graphite sheet 1, with attachment to each other along their edges via adhesive tapes 7 and 8. With this assemblage, the graphite sheet is applied to a battery cover (not shown). FIG. 2C is a cross section taken along A-A′ of FIG. 2A.
When the battery cover has a small area, however, it may be difficult to provide the protective films with edges that adhere to each other. This case may lead to product defects.
With regard to a related art, reference may be made to Korean Patent No. 1189058 (issued on Oct. 2, 2012, titled “A method for manufacturing a sheet for NFC antenna”).